Jon Chatburn

MSc Candidate, Zoology (UBC) BSc Honours (Bishop's) Contact Info: Department of Zoology University of British Columbia 6270 University Blvd. Vancouver, British Columbia Canada, V6T 1Z4 Tel: (604) 822-5799 FAX: (604) 822-2416 jonchatburn@hotmail.com chatburn@zoology.ubc.ca

In recent years there has been increasing interest in the adaptive origins of the respiratory control system in vertebrate groups, specifically the neural mechanisms generating the respiratory rhythm and the influencing factors that produce different breathing patterns. 

Amphibians, in many respects, represent the evolutionary link between aquatic and terrestrial vertebrates and therefore serve in providing insight into the physiological, morphological, and neurological adaptations that were required for the transition to life on land. 

Most anuran amphibian species exhibit breathing patterns where the buccal cavity is ventilated continuously, considered a remnant of gill ventilation, and the lungs intermittently, or episodically.  It is believed that these ventilatory patterns represent two separate but coordinated rhythms produced by separate rhythm generators.  It is proposed that neurons responsible for respiratory rhythm generation in frogs lies somewhere within the medulla and that descending inputs from the midbrain are responsible for the clustering of lung breaths into episodes. 

My work will investigate central rhythm generation in the bullfrog (Rana catesbeiana) and to establish the location of the CRG’s responsible for lung and buccal ventilation. My projects aim is to test the hypothesis that in the caudal medulla of the bullfrog brainstem, specifically the area between the Vth and Xth cranial nerves, there exists multiple segmental rhythm generators.  One set of caudal bilateral oscillators that are responsible for production of the buccal ventilatory rhythm, and another set of rostral bilateral oscillators that are responsible for the production of the lung ventilatory rhythm.